Re: git diff-files weirdness (bug?)

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: May 23, 2008, 16:14 UTC
Message-ID: <alpine.LFD.1.10.0805230906110.3081@woody.linux-foundation.org>
In-Reply-To: <b0943d9e0805230720h61cbabbbw180908e1b28a34cc@mail.gmail.com>

Looks like a real bug.

On Fri, 23 May 2008, Catalin Marinas wrote:

Show 19 quoted lines

>
> I was investigating a bug in "stg refresh" failing with moved files
> and noticed that it was caused by Git (HEAD pulled yesterday):
> 
>   git init
>   touch a
>   git add a
>   git commit -m "test"
>   git mv a b
> 
> These are OK:
> 
>   git diff-files -- a
>   git diff-files -- b
> 
> These fail:
> 
>   git diff-files -- a b
>   git diff-files -- a c

Yes, that's buggy.

What happens is that we get to run_diff_files_cmd(), but then we don't actually do "run_diff_files()", because we go into the NO_INDEX case:

	if (DIFF_OPT_TST(&revs->diffopt, NO_INDEX)) {
		...

instead.

Which in turn is because "setup_diff_no_index()" is broken.

And I think "setup_diff_no_index()" is broken exactly because it sees that '--' and then totally ignores it and says "if I see two paths, we'll say it's the non-index case".

		Linus